diff --git a/web/utils/tooltip-utils.js b/web/utils/tooltip-utils.js
--- a/web/utils/tooltip-utils.js
+++ b/web/utils/tooltip-utils.js
@@ -12,6 +12,7 @@
   reactionSeeMoreLabel,
 } from '../chat/chat-constants.js';
 import type { PositionInfo } from '../chat/position-types.js';
+import { navigationSidebarTooltipStyle } from '../navigation-sidebar/navigation-sidebar-constants.js';
 import { calculateMaxTextWidth } from '../utils/text-utils.js';
 
 export const tooltipPositions = Object.freeze({
@@ -407,9 +408,33 @@
   };
 }
 
+function calculateNavigationSidebarTooltipSize(
+  tooltipLabel: string,
+): TooltipSize {
+  const {
+    paddingLeft,
+    paddingRight,
+    paddingTop,
+    paddingBottom,
+    height: contentHeight,
+  } = navigationSidebarTooltipStyle;
+
+  const marginLeft = 24;
+  const tooltipLabelTextWidth = calculateMaxTextWidth([tooltipLabel], 14);
+
+  const width = marginLeft + paddingLeft + tooltipLabelTextWidth + paddingRight;
+  const height = paddingTop + contentHeight + paddingBottom;
+
+  return {
+    width,
+    height,
+  };
+}
+
 export {
   findTooltipPosition,
   getTooltipPositionStyle,
   calculateMessageTooltipSize,
   calculateReactionTooltipSize,
+  calculateNavigationSidebarTooltipSize,
 };